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A252178
Number of length 2+2 0..n arrays with the sum of the maximum minus the minimum of adjacent triples multiplied by some arrangement of +-1 equal to zero.
1
12, 49, 132, 285, 536, 917, 1464, 2217, 3220, 4521, 6172, 8229, 10752, 13805, 17456, 21777, 26844, 32737, 39540, 47341, 56232, 66309, 77672, 90425, 104676, 120537, 138124, 157557, 178960, 202461, 228192, 256289, 286892, 320145, 356196, 395197
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = (1/6)*n^4 + (7/3)*n^3 + (29/6)*n^2 + (11/3)*n + 1.
Conjectures from Colin Barker, Dec 01 2018: (Start)
G.f.: x*(12 - 11*x + 7*x^2 - 5*x^3 + x^4) / (1 - x)^5.
a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n>5.
(End)
EXAMPLE
Some solutions for n=6:
..4....2....0....4....2....6....2....1....4....1....4....4....2....4....2....2
..6....2....2....5....2....6....2....1....3....1....5....1....6....3....4....0
..0....0....3....1....1....0....4....6....2....2....0....6....0....4....2....6
..5....2....0....2....1....5....4....5....1....2....2....5....3....4....3....0
CROSSREFS
Row 2 of A252177.
Sequence in context: A022282 A009959 A009950 * A218832 A307921 A288516
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 15 2014
STATUS
approved